A heat treating apparatus that performs so-called tempering by heating and cooling a metal member that is a treatment object conventionally performs cooling treatment by placing the treatment object that has been heat treated midway in a flow path of a cooling gas that circulates in a heat treating furnace.
Specifically, the treatment object is placed in a cooling chamber that is formed within the heat treating furnace, and by supplying a coolant gas to this cooling chamber and rotating a fan, the coolant gas is circulated (refer to Patent Document 1).
In this kind of heat treating apparatus, since a pressurized coolant gas is used, the cooling chamber is constituted by a pressurized container. For this reason, the motor that rotates the fan is arranged inside of the pressurized container that serves as the cooling chamber.
However, a motor that can be used inside of a pressurized container is costly due to its special features, so using a moderately priced general-purpose motor has been desired. In the case of using a general-purpose motor, in order to transmit the rotation of the general-purpose motor that is arranged outside of the pressurized container, it is necessary to pass the output shaft of the general-purpose motor or the rotating shaft that is connected thereto through the container wall of the pressurized container and arrange a shaft seal structure between the output shaft or rotating shaft and the container wall. A magnetic seal, for example, has been proposed as the shaft seal structure that can be used in the container wall of the pressurized container.
Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2005-29872
Patent Document 2: Japanese Granted Patent Application, Publication No. H05-42482
However, since the interior of the pressurized container that serves as the cooling chamber is raised to a pressure of, for example, 30 atm (3.0 MPa), the problem arises of not being able to readily seal the container with the magnetic seal.
The present invention was achieved in view of the above circumstances, and has as its object to provide a shaft seal structure that is capable of being suitably applied to a rotating shaft that passes through a container wall of a pressurized container, a cooling treatment apparatus that is provided with this shaft seal structure, a multi-chamber heat treatment apparatus, a pressure regulating method, and an operating method.